Microwave radio frequency (RF) transmission systems typically are point-to-point, and thus often utilize waveguides to focus, or restrict, the direction of propagation of the electromagnetic (EM) signaling to a desired direction. To provide a microstrip-to-waveguide transition, a microstrip feedline typically is inserted near the closed end of the waveguide, which then acts to either to focus EM signaling emitted by the feedline or to focus received EM signaling to the feedline. Conventionally, the microstrip-to-waveguide transition is achieved by introducing the microstrip feedline through an aperture in a transverse wall of a monolithic waveguide. Impedance matching is achieved by shorting a back wall of the waveguide proximate to the microstrip feedline by locating the feedline within a quarter-wavelength of the EM signaling of the back wall. In some conventional approaches, this spacing is achieved by partially filling the back of the waveguide with dielectric material and then inserting the microstrip feedline. However, errors in the fabrication of the microstrip feedline or misalignment when inserting the microstrip feedline into the waveguide can result in erroneous positioning of the microstrip feedline relative to the back wall, and thus can degrade the performance of the microstrip-to-waveguide transition. The impact of such fabrication and assembly errors is particularly manifest in systems intended for communicating millimeter-wave (mmW) frequencies of 30 gigahertz (GHz) and higher due to the relatively tight design tolerances for such systems.